Browsing by Issue Date

Sort by: Order: Results:

Now showing items 21-40 of 24298
  • Olenius, Tinja (Helsingin yliopisto, 2015)
    Formation of aerosol particles from condensable vapors is a ubiquitous phenomenon in the atmosphere. Aerosols can affect regional and global climate, as well as visibility and human health. The work of this thesis contributes to the numerous efforts made to build understanding of atmospheric particle formation mechanisms. The focus is on the first molecular-level steps, where clustering of individual gas-phase molecules initiates the process, and the applied method is dynamic cluster population modeling. Sets of sub-2 nm molecular clusters are simulated in conditions relevant to the atmosphere or laboratory considering vapor production, external sinks for clusters and vapors, cluster collision and evaporation processes, and in some cases also ionization and recombination by generic ionizing species. Evaporation rates are calculated from the cluster formation free energies computed with quantum chemical methods. As sulfuric acid has been shown to be the key component in particle formation in most boundary layer locations, the majority of the work presented here concentrates on simulating sulfuric acid-containing clusters in the presence of potentially enhancing species, namely ammonia and amines. In laboratory experiments, these base compounds have been found to be capable of enhancing sulfuric acid driven particle formation to produce formation rates around the magnitude observed in the atmosphere. This result is reproduced by the cluster model. In this work, the performance of the modeling tools is validated against experimental data also by comparing simulated concentrations of charged sulfuric acid ammonia clusters to those measured with a mass spectrometer in a chamber experiment. Examination of clustering pathways in simulated sulfuric acid ammonia and sulfuric acid dimethylamine systems shows that the clustering mechanisms and the role of ions may be very different depending on the identity of the base. In addition to predictions related to cluster formation from different precursor vapors, the model is applied to study the effects of varying conditions on the qualitative behavior of a cluster population and quantities that have been deduced from measured cluster concentrations. It is demonstrated that the composition of the critical cluster corresponding to the maximum free energy along the growth pathway cannot be reliably determined from cluster formation rates by commonly used methods. Simulations performed using a simple model substance show that cluster growth rates determined from the fluxes between subsequent cluster sizes are likely to differ from the growth rates deduced from the time evolution of the concentrations as in experiments, with the difference depending on the properties of the substance as well as ambient conditions. Finally, the effect of hydration and base molecules on sulfuric acid diffusion measurement is assessed by mimicking an experimental setup. Applications of cluster population simulations are diverse, and the development of these types of modeling tools provides useful additions to the palette of theoretical approaches to probe clustering phenomena.
  • Karhula, Kati (Helsingin yliopisto, 2015)
    Health care personnel often have irregular working hours and stressful work characteristics, which may challenge employees possibilities to sleep and recover sufficiently. The aim of this study was to examine the association of stressful work characteristics, measured as job strain, with sleep and psychophysiological recovery in shift working health care professionals. As part of the Finnish Public Sector Study, 95 participants were recruited from hospital wards that belonged to the top (high job strain, HJS, n=42) or bottom quartiles on job strain (low job strain, LJS, n=53) as determined by the average job strain score among the employees of the ward. These participants experienced job strain at least as high (HJS group) or as low (LJS group) as the average on their ward. Measurements included a Trier Social Stress Test (TSST), and 3-week field measures of sleep-wake rhythm with sleep diary and actigraphy. The 3-week rosters included three pre-selected, circadian rhythm and recovery controlled measurement days, one morning shift, one night shift and a day off, and the following measurements: ratings of sleepiness (Karolinska Sleepiness Scale), Psychomotor Vigilance Test (PVT), 24h heart rate variability (HRV) measurements and saliva samples of stress biomarkers (cortisol and alpha-amylase). The rosters of the HJS group included more single days off and quick returns than the rosters of the LJS group. Severe sleepiness (KSS score of ≥7) was more common in the HJS group in quick returns. The HJS group reported poorer recovery from all work shifts and after morning shifts than the LJS group. High job strain was not associated with extended working hours. The HJS group had more difficulties in initiating sleep after evening shifts, more often reduced sleep efficiency before morning shifts, and took fewer and shorter naps before the first night shift than the LJS group. Additionally, the HJS group had more often lapses in the PVT during night shifts. Insufficient sleep (31%) and sleep complaints (often 68%) were common in shift workers regardless of the job strain group. The TSST resulted in, on average, a 2.27-fold increase in cortisol concentration in the HJS group and a 1.48-fold increase in the LJS group (non-significant group difference). The HJS group also had higher salivary alpha-amylase levels 30 minutes after awakening in the morning shift. Apart from that, the salivary cortisol and alpha-amylase levels, profiles and total secretion showed no statistically significant stress group differences. Heart rate and HRV, before and during sleep, were similar in both job strain groups. Shift work contributed to impaired sleep in both the high and low job strain groups, although the sleep impairments were more pronounced in the HJS group. Associations between job strain and psychophysiological stress-related reactions and recovery were modest. Intervention studies are needed to determine whether increasing recovery time by reducing the number of quick returns and single days off would also reduce job strain and improve sleep quality among shift workers. Emphasising the importance of sufficient sleep might promote shift workers´ recovery and well-being.
  • Rastenberger, Anna-Kaisa (Helsingin yliopisto, 2015)
    The dissertation deals with the internationalisation of contemporary Finnish photographic art over the past three decades. The study is composed of five research articles (2006 - 2013) framed by a theory-oriented introduction. It examines the discourses and definitions related to the internationalisation of Finnish photographic art. The material informing the research consists of public documents, text, and images, along with 20 thematic interviews with actors in the field of photography. Each of the four chapters making up the theoretical introduction takes the perspective of distinct research tradition. The first considers photographic art research as a part of cultural studies, while the second considers it in connection with discourse-oriented visual studies. The third chapter deals with field research in the art realm, and the fourth adopts the perspective of contemporary interview-based research. Each of the five articles focuses on the construction of a distinct international or internationalisation project, along with the motives and goals behind it and that case project s impact on the field of domestic Finnish photography. In the articles, the cases for study of the photographic field are reconstructed for study in light of diverse concepts. The research examines, for instance, how the concepts national , modern , and post-modern were used in the early 1990s to describe the way in which photographic art should be approached. In the same era, photographic art education played a central role in setting the boundaries honoured by the photography field and establishing the relationship to internationalisation. The article highlights the notion of generation as a concept of struggle. It often appears in the context of the education system. Later, in the early 2000s, the increased international acclaim of Finnish photographic art drew attention to definitions of photographic artist , photographic work of art , and curator . With the new millennium, an economic logic spread in the art world and came to influence art-related discourse and practices. The cultural policy debate highlighted the economic importance of culture and the arts; the economic value of art became king. Two of the articles discuss the concept of brand, thereby rounding out the analysis with consideration of the present day. They observe branding of the visual arts as a contemporary but also historical phenomenon. The dissertation highlights that, even if there have been frequent efforts to manifest consensus and unity within the Finnish photographic art scene in the context of internationalisation projects, the discussions dealing with them have encouraged the actors in the field of photography to articulate their own views and thereby bring out the polyphony of photographic art and the divergent objectives of the actors.
  • Gabryelczyk, Bartosz (Helsingin yliopisto, 2015)
    The possibility of controlling interactions at interfaces and surfaces of solid materials is highly interesting for a wide range of materials-related nanotechnological applications, for example, colloidal systems, adhesives, biosensors, biomimetic composite and biomedical materials. In Nature, many proteins and peptides possess the ability to recognize, specifically bind, and modify the surfaces of solid materials through sophisticated mechanism of molecular recognition. These properties have been developed during evolution via successive cycles of random mutations and selection. The natural evolution processes can be mimicked in the laboratory scale with the use of a directed evolution approach, for instance, based on the selection of short material-specific peptides from the combinatorial libraries displayed on the surface of bacteriophages or bacterial cells. Selected from billions of different variants, material-specific peptides can be studied by experimental and computational methods to define their sequence, structure, and binding properties. Subsequently, they can be engineered in order to improve their binding affinity and tailor their function for practical applications. The studies presented in this thesis show how phage display was used to identify peptides binding to diamond-like carbon (DLC). DLC is an amorphous form of carbon, with chemical and physical properties resembling natural diamond. It is used as a coating material in many industrial and biomedical applications. Peptides binding to DLC were selected form a combinatorial phage display library. Their binding and molecular basis of the function were investigated in different molecular contexts (when displayed on the phage surface, forming fusion proteins, or present in free soluble form), using multiple independent methods. It was also demonstrated that the peptides can be used in nanotechnological applications, i.e., as a self-assembling coating on the DLC surface, and for controlling properties of a colloidal form of DLC. Besides finding and characterizing peptides binding to DLC, the thesis also highlights different challenges of the directed evolution techniques, for example, selection of target unrelated peptides during biopanning, and the necessity of multiple independent ways of analyzing the functionality of selected peptides.
  • Majasalmi, Titta (Helsingin yliopisto, 2015)
    The aim of this dissertation is to assess the accuracy of different ground reference methods used to validate satellite based leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (fPAR) products. LAI and fPAR are strongly linked, although they principally and practically measure different properties: LAI quantifies the areal interphase between soil and atmosphere, whereas fPAR quantifies the energy available for photosynthesis. Until now, the development of remote sensing based methods to estimate LAI and fPAR in a boreal forest has been hindered by the scarcity of ground data, which is required to validate and develop existing algorithms. The aim of the first part of this dissertation was to assess the impacts of different methodological approaches to estimate LAI in boreal forests, and to validate satellite based LAI products. Results showed that the accuracy of ground based LAI estimates is sensitive to both the retrieval methods and sampling scheme used to collect the optical LAI data. The satellite based measurements of LAI demonstrated a large temporal variability in LAI. The second part of the dissertation focused on measuring and modeling fPAR in a boreal forest. A new scheme for measuring and modeling ground reference fPAR based on photon recollision probability was presented in this dissertation. Ground reference fPAR is usually estimated only for the forest canopy layer. This study is among the first ones to validate the new global satellite based fPAR product called GEOV1 using data of both the forest canopy and understory layers from boreal forests. Results showed that satellite based fPAR products may correspond better with the total fPAR, instead of only the forest canopy fPAR as has often been presumed.
  • Hildén, Timo (Helsingin yliopisto, 2015)
    Gas Electron Multiplier (GEM) detectors are special of position sensitive gas filled detectors used in several particle physics experiments. They are capable of sub- millimeter spatial resolution and energy resolution (FWHM) of the order of 20%. GEM detectors can operate with rates up to 50 kHz/mm2, withstand radiation excellently and can be manufactured up to square meter sizes. This thesis describes the Quality Assurance (QA) methods used in the assembly of 50 GEM detectors for the TOTEM T2 telescope at the LHC at CERN. Further development of optical QA methods used in T2 detector assembly lead into development of a unique large-area scanning system capable of sub-µm resolution. The system, its capability and the software used in the analysis of the scans are described in detail. A correlation was found between one of the main characteristics of the detector, the gas gain, and the results of the optical QA method. It was shown, that a qualitative estimation of the gain can be made based on accurate optical measurement of the microscopic features of the detector components. Ability to predict the performance of individual components of the detectors is extremely useful in large scale production of GEM based detectors.
  • Wang, Chang-Fang (Helsingin yliopisto, 2015)
    Anticancer drugs inhibit the cancer growth by killing the rapidly dividing cancer cells. However, anticancer drugs also kill the dividing healthy cells and cause severe damage to healthy tissues. More specific delivery of the cancer drugs to the cancer tissue can increase the drug delivery efficiency and reduce the drug s side effects. Nanocarriers can increase the solubility of poorly-water soluble anticancer drugs and be modified for targeted drug delivery and theranostic applications. For efficient drug delivery, the drug loading capacity has been one of the key issues for the development of nanoparticle (NP)-based drug delivery systems. The biocompatible and biodegradable porous silicon (PSi) nanomaterial presents high drug loading capacity and tunable surface chemistry which renders it an ideal candidate as a drug delivery carrier. Chemical surface modification, which is one of the approaches to improve the nanomaterials properties, can lead to a stable nanosystem for further drug delivery applications. The main aim of this dissertation was to employ chemical approaches and surface modified PSi nanoparticles (NPs) to improve the drug delivery efficiency for potential cancer therapy applications. Incorporating targeting moieties to the surfaces of the nanocarriers, such as targeting peptides, can increase the nanocarrier s accumulation into the cancer tissue after the intravenous administration. In this thesis, surface modification of amine-terminated PSi NPs was achieved with targeting peptides (RGDS and iRGD) via strain-promoted azide-alkyne cycloaddition click reaction. The functionalization of the PSi NPs with the targeting peptides did not comprise the drug loading capacity, but enhanced the cellular uptake and the drug delivery efficacy of the PSi NPs in vitro. In addition to the targeting NP surface modifications, a multifunctional nanosystem was prepared with simultaneous fluorescence- and radio-labeling, and iRGD surface modification of the carboxylic acid-terminated PSi NPs. Both labelings were accessible for the in vivo biodistribution evaluation in mice by single-photon emission computed tomography and X-ray computed tomography, and ex vivo by immunofluorescence staining, respectively. The iRGD modification enhanced the tumor uptake of the PSi NPs after the intravenous administration. In order to reduce the plasma protein adsorption onto the PSi NPs, five bioactive molecules (peptides and hydrophilic anti-fouling polymers) were used to modify the surface of alkyne-terminated PSi NPs using copper-catalized click chemistry. Dextran 40 kDa modified PSi NPs presented enhanced cellular uptake and the least protein adsorption of all the tested NPs. Furthermore, the chemical conjugation of drug molecules was studied. The targeting peptides were successfully conjugated to antisense interleukin-6 via copper-catalyzed [3+2] azide-alkyne cycloaddition for targeted angiogenic anti-inflammation in cancer. Finally, anticancer drug methotrexate (MTX) was chemically conjugated to the cationic PSi NPs and demonstrated to increase the cellular uptake of MTX with up to 96 h sustained drug release. A hydrophobic anti-angiogenic drug, sorafenib, was also loaded to the MTX-conjugated PSi NPs, and the dissolution rate of this drug was considerably increased. In conclusion, in this thesis different chemical approaches were used to biofunctionalize PSi NPs and to prepare drug-conjugates formulations for potential anti-cancer applications.
  • Lindfors, Anne-Marie (Helsingin yliopisto, 2015)
    Abstract This study investigates the translation of anglophone West African novels in Finland. It addresses the question of what happens to the linguistic and cultural hybridity present in the source texts when these are translated into Finnish. Anglophone West African novels often contain words borrowed from local African languages as well as unfamiliar cultural features and nonstandard language varieties, which can be called africanised English. The writers of these texts bend the language of the ex-colonisers to add local colour to their texts and to make the language better express local life. In addition, the use of africanised English may aim at weakening the hegemonic position of English, dismantling the colonial structures in the former colonies and changing the old stereotypes about Africa, i.e. it may have political and ideological functions. Thus far, fifteen anglophone West African novels have been translated into Finnish. The material of the study consists of twelve of these, nine from Nigeria and three from Ghana, and their translations into Finnish. The selected novels were written by nine authors, translated by nine different translators and published in Finland between 1963 and 2010. My hypothesis was that africanised English in hybrid West African novels has been normalised at least to a certain extent in the target texts, as there are no corresponding language varieties in Finnish, and also because the normalisation of linguistic and cultural difference is a general trend in translation practice. The linguistic and cultural details of African source texts and the translation of these features into Finnish have not received much attention in Finland before this study. The method of analysis was descriptive and comparative. I first studied what authorial techniques anglophone West African writers used to africanise their texts, after which pairs of target-text solutions and source-text problems were extracted and the translation relationships between them described. The texts were analysed both qualitatively and quantitatively, with a view to discovering general patterns in the relationships which would make it possible to establish the concepts of translation and to speculate on the nature of the norms that have governed the translating of the texts. The period of 47 years covered by my material was expected to make it possible to detect changes that may have taken place in Finnish translation practice and norms. Contrary to my expectation, the results of the analysis show that the translators of the twelve texts were inclined to retain the hybridity present in the source texts (foreignisation), but it was also observed that more recent target texts showed a trend towards less marked renderings (domestication). Both translation approaches have their problems: foreignised target texts may be considered uninteresting and even incomprehensible by target readers, while domesticated translations may affect the functions of the postcolonial source texts by maintaining the prevailing attitudes towards Africa that circulate in the target culture.
  • Snellman, Jan (Helsingin yliopisto, 2015)
    The mathematical description of turbulence is one of the greatest unresolved problems of modern physics. Many targets of astrophysical research, such as stellar convection zones and accretion discs, are very turbulent. Especially, the understanding of stellar convection zones is important for the theory of stellar evolution. Therefore, it is necessary to use approximate descriptions for turbulence while modelling these objects. One approximate method for describing turbulence is to divide the quantities under study into mean and fluctuating parts, the latter of which represent small scale changes present in turbulence. This approach is known as the Reynolds decomposition, which makes it possible to derive equations for the mean quantities. The equations acquired depend on correlations of the fluctuating quantities, such as the correlations of the fluctuating velocity components known as the Reynolds stresses, and turbulent heat and passive scalar fluxes. A mathematically precise way of handling these correlations is to derive equations also for them, but the resultant equations will depend on new, higher order correlations. If one derives equations for these new correlations, a new set of even higher order correlations is involved, and the equation system will not be closed. This is called the closure problem. The closure problem can be circumvented by using approximations known as closure models, which work by replacing the higher order correlations with lower order ones, thereby creating a closed system. Second order closure models, in which the third order correlations have been replaced by relaxation terms of second order, are studied in this Thesis by comparing their results with those of direct numerical simulations (DNS). The two closure models studied are the minimal tau approximation (MTA) and the isotropising variable relaxation time (IVRT) closure. The physical phenomena, to which the closures were applied, included homogeneous isotropically forced turbulence with rotation and shear, compressible as well as homogeneous Boussinesq convection, decaying turbulence, and passive scalar transport. In the case of homogeneous isotropic turbulence it was found that MTA is capable of reproducing the DNS results with Strouhal numbers of about unity. It was also found that the Reynolds stress components, contributing to angular momentum transport in accretion discs, can change sign depending on rotation rate, which was seen in studies of compressible convection too, meaning that convection can potentially contribute to accretion of matter. Decaying turbulence studies indicated that the relaxation time scales occurring in the relaxation closures tend to constant values at high Reynolds numbers, and this was also observed when studying passive scalar transport. However, in studies concerning Boussinesq convection no asymptotic behaviour was found as a function of the Rayleigh and Taylor numbers. The correspondence of the closure models to direct numerical simulations is found to be generally achievable, but with varying quality depending on the physical situation. Given the asymptotic behaviour of the optimum closure parameters for forced turbulence, they can be considered universal in this case. For rotating Boussinesq convection the same conclusion cannot be drawn with respect to the Rayleigh and Taylor numbers.
  • Pulkkinen, Henni (Helsingin yliopisto, 2015)
    Overfishing and environmental changes impose high risks on the wellbeing of the world's fish stocks. It is commonly acknowledged that fisheries management should be risk averse, following the principles of the precautionary approach, but unfortunately the statistical stock assessment methods often lack the ability to estimate the uncertainties related to their results. Further challenges arise from the fact that stocks which are in the most desperate need of a stock assessment are often data poor and resources to gather new data from them are scarce. Bayesian statistical inference can be utilized to conduct stock assessments cost-efficiently since these methods provide a formal way to combine information from various sources including databases, literature and expert knowledge. Bayesian inference is essentially a learning process where existing information is combined into a prior distribution, which is further updated with the most recent data. The result, a posterior distribution, expresses the best available knowledge about the phenomenon, including the related uncertainty. Furthermore, Bayesian hierarchical models enable learning between similar units, for example, stocks of the same or related species. This thesis consists of four studies that use Bayesian hierarchical models to improve knowledge in the fisheries stock assessment. Correlations between biological parameters, arising from different life history strategies among species, are utilized in paper [I] so that a data rich set of length-weight parameters can reduce the uncertainty of length-fecundity parameters for a data poor species. In paper [II], similarities between stocks of Atlantic salmon are used to estimate the stock specific key parameters of eggs-to-smolts relationship. A predictive distribution of this key parameter is also estimated, and could be used as an informative prior in a subsequent study of another Atlantic salmon stock. In addition, a hierarchical model is built to study structural uncertainty, estimating posterior probabilities of competing functional forms that describe the eggs-to-smolts survival at different juvenile densities. The Bayesian approach makes it possible to conduct analyses sequentially, as in the case of Baltic salmon stock assessment reviewed in paper [III]. Sequential analysis is useful if a stock assessment is complex and computational power does not enable analysis of all observation models at the same time. Thus, the Bayesian methods permit the creation of complex model frameworks, where incentives for structural choices arise rather from the biological process, than from the requirements or limitations of the datasets. The analysis of acoustic survey information to estimate herring resources at Bothnian Sea (paper [IV]) is another example of a computationally intensive model that has been built on the basis of available background information. This includes on one hand, the technical knowledge about the survey, and on the other hand, the biological knowledge about the spatial distribution of the fish.
  • Alestalo, Paula Kaarina (Helsingin yliopisto, 2015)
    ABSTRACT The general objective of this thesis was to study management and leadership in the Public Dental Service (PDS) in Finland during the major Dental Care Reform in 2003–2011. The specific aims were to study 1) how dentists became leaders in the PDS and 2) what characterised their leadership, 3) distribution of leadership positions between women and men, 4) chief dentists’ position in the municipal hierarchy, as seen from their own superiors’ and subordinates’ points of view and 5) chief dentists’ attitudes to the Dental Care Reform and the changes it caused in the work environment. Four questionnaire surveys based on four data sets were carried out in 2003. The target groups were the chief dentists of the municipal PDS units (health centres) (n=265), the chief physicians (n=233), the line managers (superiors) of the chief dentists, PDS dentists who were subordinates to the chief dentists (n=365), and the chairpersons of Municipal Boards of Social Affairs and Health (MBSH) (n=233). In 2011, the target group was the chief dentists alone (n=161). Factor analysis, linear regression analysis, parametric and non-parametric tests were used in the analysis of the materials. The results showed that only fewer than a fifth (17%) of chief dentists were full-time leaders in 2011 and they worked in the largest health centres. The rest also provided patient care, to varying degrees. In 2003 and 2011, nearly two thirds (62%) of the chief dentists identified themselves as leaders instead of seeing themselves only as dentists among other dentists in the PDS, though fewer than a third (31%) of them had applied for their posts. More precisely, just 21% of female and 43% of male chief dentists (p<0.001) had applied for the chief dentist posts they held. Chief dentists felt they were better people-oriented leaders than goal-oriented managers (p<0.001). Nevertheless, 49% p<0.001) of their job satisfaction was explained by the fact that they were motivated to lead, their position as superiors to their subordinates was good, they had enough (3-4 on a scale 1-4) decision making power, they were good goal-oriented managers (good in sum variables ≥3 on a scale 1-4 from very bad to very good), and had received enough (3 on a scale 1-3) leadership education. In addition, if they had a good position as subordinates to their superiors, chief physicians and MBSH chairpersons (p<0.001), and when they had applied for their posts, they felt contented (p<0.001). In 2003, their subordinates, the PDS dentists, appreciated their people-oriented female superiors highest. Chief dentists themselves as subordinates felt they received little feedback and support from their superiors (chief physicians), and their own subordinates, the PDS dentists, felt the same (p<0.001). Chief dentists’ superiors (chief physicians and MBSH chairpersons) evaluated the chief dentists as good managers and leaders, whereas the chief dentists’ subordinates evaluated their superiors in less positive terms. In 2003, more than half (59%) of the chief dentists were very positive (4 on a scale 1-4) towards the recently introduced reforms of the Health Insurance Act (HIA) promoting adults’ treatment in the private sector by increasing reimbursement for dental care. Fewer than half (43%) were very positive towards the reform of the Primary Health Care Act (PHCA) improving adults’ access to care in the public sector (p<0.001). In 2011, only 20% totally agreed (4 on a scale 1-4) that the implementation of the Dental Care Reform had succeeded. The respondents’ general opinion was that the timetable for the Reform was too tight and not enough resources were allocated. In general, the chief dentists considered their position as isolated and rather weak in the municipal hierarchy. Effective and rewarding leadership in the PDS needs more attention in the future.
  • Hämäläinen, Harri (Helsingin yliopisto, 2015)
    ABSTRACT The purpose of this study was to explore bone mineral content (BMC) and bone mineral density (BMD) development and related factors in patients with rheumatoid arthritis (RA) between 15 and 20 years from disease onset (I), in premenopausal women with RA (II), and in young adults with juvenile idiopathic arthritis (JIA) (III), and to ascertain osteoporosis (OP) drug use in patients with early RA (IV). BMD of the lumbar spine and the femoral neck were measured by dual-energy X-ray absorptiometry in patients with RA in two longitudinal studies and in young adults with JIA in a cross-sectional study. In assessing BMD at 15 years from disease onset in an inception cohort of RF-positive RA patients, it was found that eighteen out of 59 (31%) patients had OP. However, the decreases in central bone mineral in this patient group were of low degree and after the subsequent five years no essential change in central BMD was found. None of the explanatory variables: sex, age, ESR, HAQ, Larsen score, and cumulative prednisolone dose between 15-20 years from disease onset, proved to be a significant predictor of BMD change at the lumbar spine and femoral neck from 15- to 20-year check-ups (I). In assessment of BMC and BMD development in premenopausal, regularly cycling RA patients with and without GCs and in controls, it was found that RA patients with GCs had lower BMD values than those without GCs at commencement of follow-up. Furthermore, the mean BMD decreased significantly in both lumbar spine (P 0.002) and femoral neck (P smaller than 0.001) only in the RA patients with GCs during the 2-year follow-up. However, there was no statistically significant difference between the three groups in change in BMC or projectional area in the lumbar spine or femoral neck. Comparing results on bone mineral density change between the three groups it is relevant to report changes both in bone mineral content and in projectional area to clarify the basics of the bone mineral density change. BMD is expressed as BMC per projectional area. Only weight was found to be a significant predictor of BMD change (II). Assessment of BMC and BMD development in young adults with JIA and controls assumed to have reached their peak bone mass, showed that three (2.6%) out of 116 patients with JIA had OP. The male and female JIA patients had lower weight- and height-adjusted BMD values in the femoral neck than the controls. Dividing the patients into two groups, those with active and those with inactive JIA, both groups had lower BMC values in the femoral neck than the controls (P smaller than 0.001). Comparing BMC values in the femoral neck in both men and women with JIA a difference was found only among men (P 0.006). Among men, use of GCs and weight were significantly associated with BMC in the femoral neck. Among women, use of GCs, weight and also height were associated statistically significantly with BMC in the femoral neck, and among women GC use and height were also associated with BMC in the lumbar spine (III). A total of 14 878 incident cases of RA were studied when evaluating the implementation of pharmaceutical OP drug use. Out of this total, 1351 (9%) patients with RA had purchased OP drugs, mainly bisphosphonates, during the first year after commencement of antirheumatic treatment. Of GC users, 14% of women and 6% of men were prescribed OP drugs. In addition, 8% of females and 3% of males not taking GCs received OP medication. Women were more prone to use OP medication. Of the RA patients who took GCs, 38% of women and 24% of men received concomitant calcium and vitamin D preparations by prescription during the same year, whereas the corresponding percentages for patients without GCs were 21% and 13%. (IV). Study results suggest that bone loss takes place in earlier disease course in RA and JIA and bone loss is in the long-term disease course in RA of low degree. Further studies are needed to elucidate bone loss and OP development in early rheumatoid arthritis and to better focus the timing and means of OP prevention.
  • Kluger, Nicolas (Helsingin yliopisto, 2015)
    Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED, OMIM 240300) is a rare autosomal recessive disorder caused by mutations in the autoimmune regulator (AIRE) gene located on chromosome 21 (21q22.3). AIRE deficiency causes a loss in central immune tolerance, leading to the failure to eliminate autoreactive T cells in the thymus and allowing their escape to the periphery. Because of a founder effect, APECED is particularly prevalent in Finland (1/25,000) but is observed worldwide with variable prevalence. APECED patients are susceptible to mucocutaneous candidiasis and multiple endocrine autoimmune diseases such as primary hypoparathyroidism, adrenal insufficiency, primary hypogonadism, type 1 diabetes, hypothyroidism, and hypophysitis. They may also develop additional nonendocrine autoimmune diseases, such as alopecia areata/totalis, vitiligo, gastro-intestinal (GI) diseases, keratitis or tubulointerstitial nephritis (TIN). In addition, the patients typically develop a variety of serum tissue-specific autoantibodies, which are predictive of the development of autoimmune disease and anticytokine antibodies such as those against type I interferons and Th17-related interleukin IL-17 and IL-22. The aim of this thesis was to study such manifestations of APECED that have not been well characterized before and also, to study health-related quality of life among Finnish APECED and Addison s disease/APS2 patients. We evaluated the clinical GI features and searched for novel markers of GI dysfunction in a Finnish cohort of 31 APECED patients. The main upper GI symptoms were dysphagia and retrosternal pain (45%) and the lower GI symptoms were constipation (48%), diarrhoea (45%) and malabsorption (16%). Previously, L-amino-acid decarboxylase (AADC) and tryptophan hydroxylase type 1 (TPH-1) antibodies have been demonstrated in APECED. AADC antibodies were found in 51% and TPH-1 antibodies in 39% of all patients. Also, a T cell response to AADC was detected in 43%. One third of the patients had autoimmune enteropathy (AIE)-related 75 kDa antigen (AIE-75, 33%) and villin (29%) autoantibodies, and antibodies against brush borders and Paneth cells (PCs) were detected in 29% and 20%, respectively. Mucosal intestinal IL-17 expression was decreased or negative in 77% of the intestinal samples. Duodenal chromogranin A and serotonin expression was absent or decreased in 50% and 66% of the patients, respectively. Of the clinical symptoms, constipation correlated with negative serotonin staining (p less than 0.05) and with AADC antibodies (p = 0.019). Importantly, we found a correlation between autoantibodies against AADC, which are critical for serotonin and DOPA synthesis, and constipation. Constipation was also associated with a lack of serotonin expression in the enteroendocrine cells (EECs). Paneth cells (PCs) were lacking in the duodenum in 20% of our intestinal samples, even though this was not associated with GI symptoms. In this Finnish APECED patient cohort, 17% (5/30) had moderate-to-severe renal failure, including 10% (3/30) with TIN requiring transplantation, haemodialysis or immunosuppressive treatment. However, the latter did not seem to be efficient in controlling disease progression. All 3 patients with TIN had circulating antibodies against the distal part of the nephron, as did 30% of all cohort cases. The pathogenic relevance of such circulating antibodies is still unclear. The immunological basis of hypoparathyroidism in APECED was explored by studying circulating calcium-sensing receptor (CaSR) and NALP5 antibodies. Although they were detected in 16 of 44 (36%) and 13 of 44 (30%) patients, respectively, we failed to find any clinically relevant statistical association. These APECED patients did not present circulating antibodies for other autoimmune diseases such as rheumatoid arthritis, celiac disease, bullous pemphigoid or pemphigus vulgaris. Some patients had antinuclear antibodies at a low-titre without clinical significance. Secondly, we evaluated the health-related quality of life among Finnish APECED and Addison s disease/APS2 patients and sought to determine which factors may predict a possible impairment. Using health-related quality of life (HRQoL) questionnaires for APECED (SF-36) and Addison s disease/APS2 patients (SF-36, 15D), we indeed observed impaired HRQoL. For the APECED patients, general health, emotional well-being and energy/vitality were the most diminished aspects of HRQoL. Among the patients with Addison s disease/APS2, compared to a large control population, physical or emotional role functioning, energy/vitality and general health were most affected. Discomfort and symptoms, vitality, and sexual activity were the most affected dimensions of the 15D scores. Affiliation with a patients association, female gender, the presence of non-APS2 inflammatory comorbidities, lower educational level and a longer disease duration were independent predictors of impaired HRQoL in these patients. Taken together, the results of this thesis show that APECED patients are genetically prone to develop autoantibodies to a multitude of tissue antigens but are still tolerant to some common autoantigens. The true clinical and biological relevance of these circulating autoantibodies has not yet been elucidated, and it is possible that they are only a reflection of T cell-mediated immunity. They may, however, have a cumulative effect and clinical disease may arise only in patients with a combination of circulating antibodies, as seen in diabetes type 1. This may explain why we failed to find any association between any single type of antibody and a given symptom. For the lower GI track manifestations, we hypothesise a cumulative effect of the autoimmunity directed against both the enteroendocrine cells and the Paneth cells, leading to a dysfunction in both the secretion of serotonin in the gut and the secretion of antimicrobiobial defensins. Such a disturbance would have an effect on the gut microbiota. The question of whether the neutralising antibodies against cytokines may have a paradoxical protective effect is open to debate. Lastly, despite having a high number of manifestations, patients with APECED seem to cope with their disease. Patients with Addison s disease have significantly impaired HRQoL compared to the general population.
  • Mäkelä, Hanna (Helsingin yliopisto, 2015)
    Roughly three-quarters of Finland s area is covered by forests. Any climatological changes influencing the danger of forest fire are important to evaluate and consider. The objective of this thesis is to study the long-term past and future changes in climatically-driven forest fire danger in Finland based on the summertime mean temperature and precipitation sum. The work is composed of two parts. In the first part, long-term gridded datasets of observed monthly mean temperatures and precipitation sums for Finland are developed. In the second part, these gridded datasets are used together with calculated values of the Finnish Forest Fire Index and probabilistic climate model simulations (from the ENSEMBLES project) to estimate the number of forest fire danger days during the summer season (June-August). The long-term variation of Finland s climatological forest fire danger is studied roughly for 100 years backwards and into the future. One of the main achievements of this thesis is that it explores the possibility of quantifying past and future fire-weather using a relatively limited database with regard to both weather variables and their spatial coverage. This enables a wider exploitation of scattered data series from earlier times and can also provide opportunities for projections using data with a low resolution. The climatological forest fire danger in Finland varies considerably from year to year. There have not been any significant increasing or decreasing trends in the number of fire danger days during the 20th century (1908-2011). On average, the highest probability of forest fire danger occurs in June and July, when a fire hazard exists on roughly 35-40% of all days. The intra-seasonal variation of fire danger has been large enough to enable the occurrence of conflagrations even though the fire danger for the season as a whole has been at an average level. Despite the projected increase in average summertime precipitation, the Finnish climate will provide more favourable conditions for the occurrence of forest fires in the future than today. This is due to increases in the mean temperature. The probability of an increase in the number of fire danger days is 56-75% in the near future (2010-2029) and 71-91% by the end of the current century (2080-2099), depending on the region. This would indicate an increase of 1-2 and 7-10 days, respectively. It is thus clearly important to further develop existing tools for the forecasting of fire danger, and to maintain the capabilities of the fire prevention, surveillance and suppression services. Future projections of all relevant meteorological variables (temperature, precipitation, humidity, evaporation and wind speed) at higher temporal and spatial resolutions, in addition to information on the type of the summertime precipitation and the length of the dry periods, would notably improve the assessment of the future climatological forest fire danger.
  • Ilinov, Andrey (Helsingin yliopisto, 2015)
    Nanotechnology became an emerging field during the last few decades. The possibility to create elements having sizes in the nanometer range provides new opportunities for medical applications, various sensors and detectors, and composite materials technologies. However, at the nanoscale the basic physical properties may change unexpectedly including chemical, mechanical, optical and electronic properties. There is still no clear understanding of all possible consequences of miniaturization on the behavior of nanostructures. This thesis is focused on the analysis of mechanical and structural (including sputtering under irradiation) properties of nanorods. By nanorods we imply structures like beams or rods, with their cross-sectional diameter measuring in nanometers and having a length several times larger than the diameter. At such sizes it becomes possible to simulate the structures atom by atom using the molecular dynamics (MD) method. In the first part of the thesis, we analyze the elastic properties of Si nanorods: how the variation in size may change the elastic moduli, the effects of oxidation and intrinsic stresses. We also check the validity of the classical continuum mechanics approach by modeling the same nanorods with the finite elements method (FEM). In the second part we investigate sputtering from Au nanorods under ion irradiation. Recent experiments had shown that there is a big enhancement of sputtering yields from Au nanorods in contrast with those from a flat surface. The yields can be as much as 1000 per individual impact. MD gives us an opportunity to analyze the sputtering process with a femtosecond resolution which is impossible by any of the existing experimental methods. We find that an explosive ejection of nanoclusters is the main factor causing such large sputtering yields.
  • Kuusimäki, Aino (2015)
    Tutkielma käsittelee kahta julkisen ja yksityisen välistä projektia, yhtä Helsingissä ja toista Berliinissä. Projekteissa yksityinen yritys toimii toimeenpanevana osapuolena sekä moderaattorina, välittävänä linkkinä kuntalaisten ja virastojen välillä. Kuntalaiset ovat kummassakin projektissa läsnä ”pyöreän pöydän” äärellä, ikään kuin tasavertaisena keskustelu- ja neuvottelukumppanina muiden kuntalaisten sekä projektien johdon kanssa. Tarkastelen tapauksia kahta teoriakokonaisuutta vasten. Ensimmäinen koskee uusliberalistista eetosta ja valtajärjestelmiä: niin kutsuttuun uuteen julkishallintoon kuuluvat muun muassahallinnon vallan hajauttaminen ja julkisten palveluiden yksityistäminen, sektoreiden välistenrajojen sumentuminen, projektiluontoisesti työskenteleminen ja kuntalaisiin suhtautuminenasiakkaina. Toinen teoriakehys liittyy osallisuuteen yhdyskuntasuunnittelussa: sosiaalisten tilojen ja kokemuksellisen tiedon merkitys on kasvanut kaupunkisuunnittelussa, mikä muuttaa oleellisesti sekä yhdyskuntasuunnittelijan ammattia että suunnitteluprosessia. Tutkin työssäni, miten uusi julkishallinto ja osallisuuden vaatimus yhdyskuntasuunnittelussa näkyvät kahdessa kaupunkisuunnitteluun liittyvässä projektissa. Kysyn, mitä hyötyä virastoille on moderaattorien palkkaamisesta, miten kasvokkaiset kontaktit ja moderaattorien läsnäolo vaikuttavat osallisuuteen ja millaisia motiiveja virastoilla on edistää osallisuutta. Primaariaineistona käytän projekteissa työskennelleiden ja yhden asukkaiden edustajan kanssa tekemiäni puolistrukturoituja asiantuntijahaastatteluita sekä lomakekyselyllä keräämiäni kokemuksia osallistetuilta kuntalaisilta. Vertailen projekteissa mukana olleiden henkilöiden kokemuksia ja käsityksiä projekteihin liittyvistä aiheista niin projektien sisäisesti kuin niitä toisiinsa rinnastamalla. Aineistoa täydentää havainnointi. Tutkimus osoittaa, että moderaattorista on hyötyä viraston tehtävien aika- ja tiedollisten resurssien lisääjänä. Moderaattori lisää työvoimaa ja ammattitaitoa lyhytaikaisiin tehtäviin ja voi toimia temaattisesti tai alueellisesti kohdennetummin kuin viraston työntekijät. Lisäksi moderaattorin avulla voidaan käydä niin kuntalaisten välisiä kuin kuntalaisten ja viraston välisiä keskusteluja suhteellisen puolueettomalla maaperällä. Tutkimuksen perusteella virastojen ja kuntalaisten välille liittyy lähtökohtaisesti jännitteisyyttä. Kuntalaiset haluaisivat nähdä vaikuttavansa osallistumiinsa hankkeisiin, mutta viranomainen ei voi luvata sitä. Moderaattori helpottaa keskusteluyhteyden luomisessa, pehmittää jännitteitä ja lisää tieto- ja aikaresursseja hankkeissa, joissa osallisuus on keskeisessä asemassa.
  • Kallajoki, Liisa (2015)
    Beta-diversity describes the change of community composition between sites. It is an important, albeit poorly understood component of biodiversity, which often represents regional diversity more profoundly than local species richness. Studying the relationship between diatom community composition and elevation increases our understanding of the mechanisms governing regional diversity patterns. Traditionally small organisms with high population densities have been thought to be omnipresent, restricted only by prevailing environmental conditions, with no biogeographical patterns, unlike those found in macro-organisms. In this thesis beta-diversity will be studied on four elevational gradients (n=64) using Sørensen, Simpson and Morisita-Horn indices. Because the relative importance of spatial control and environmental variables vary across spatial scale, I examine the change in community composition between all the sites along the elevational gradient and at a smaller scale between adjacent sampling sites. The rate of distance decay will also be examined as the halving distance of community similarity. Since total species diversity is closely associated with species range size, I will also observe Rapoport’s rule, which states that elevational ranges of species are generally wider at higher elevations than at lower elevations due to climatic variability. Linear regression and Mantel tests were the statistical methods used to study beta-diversity. Redundancy analysis (RDA) and cluster analysis were also used as multivariate methods. The effect of elevation on large scale species turnover was statistically very significant on all study gradients with both simple and partial Mantel tests (r=0.368–0.742 P=0.001). The effect of environmental variables was statistically very significant only in the Pyrenees, as opposed to the streams around the Kilpisjärvi area. The effect of elevation on small scale beta-diversity was statistically significant only in the Pyrenees (P=0.001) and Helligskogen (P<0.05). The halving distance of compositional similarity was shortest in the Pyrenees (24 % of the whole length of the gradient). A weak, but statistically significant Rapoport’s effect was observed only in Helligskogen. The findings suggest that vertical distance, i.e. elevation, was the major driver of diatom beta-diversity. The spatial structure driving beta-diversity had a greater effect on large scale species turnover than local environmental variables, except for in the Pyrenees where local biotic and abiotic factors were also statistically significant. The observed strong spatial structure thus represents large scale historical and climatic control rather than local environmental conditions.
  • Sirén, Miika (2015)
    Käyttöliittymän arviointimenetelmät voidaan jakaa kahteen eri kategoriaan: asiantuntija-arviointeihin ja empiirisiin menetelmiin. Asiantuntija-arvioinnit suorittaa käytettävyysasiantuntija, kun taas empiirisiin menetelmissä tarkastellaan testikäyttäjien tapaa käyttää testattavaa järjestelmää. Tässä tutkielmassa käsitellään kognitiivisista läpikäyntiä, simulointitestausta, käytettävyysläpikäyntiä ja käytettävyystestausta. Näistä menetelmistä kaksi ensimmäistä sijoittuu asiantuntija-arviointeihin ja kaksi jälkimmäistä empiirisiin käyttäjätesteihin. Tutkielmassa vertaillaan, millaisia käytettävyysongelmia arviointimenetelmillä löydetään. Lisäksi tutkitaan sitä, onko yhdellä menetelmällä löytynyttä käytettävyysongelmaa edes mahdollista löytää muilla menetelmillä. Vertailu tehdään suorittamalla kaikki menetelmät samaa testitehtävää käyttäen. Arvioinnin kohteena käytetään Matkahuollon ja VR:n verkkosivustoja. Arviointimenetelmillä löytyneet käytettävyysongelmat jaotellaan opittavuusongelmiin, turhaa kognitiivista työtä vaatineisiin ongelmiin, turhaa mekaanista työtä vaatineisiin ongelmiin, puuttuvaan toiminnallisuuteen liittyviin ongelmiin, tietosisällön aukkoihin liittyviin ongelmiin ja muihin ongelmiin. Työssä arvioidaan, olisiko yksittäinen ongelma mahdollista löytää muilla menetelmillä. Tutkielmassa vertaillaan, millaisia ongelmia löydettiin usealla menetelmällä. Lisäksi työssä käsitellään vain yhdellä arviointimenetelmällä löytyneitä ongelmia. Tutkielman tulosten perusteella voidaan todeta, että arviointiemenetelmillä on omat vahvuusalueensa. Kognitiivinen läpikäynti, käytettävyysläpikäynti ja käytettävyystesti auttavat opittavuusongelmien löytämisessä, kun taas simulointitestauksella voidaan paikantaa pääasiassa turhaan työhön liittyviä ongelmia. Useilla arviointimenetelmillä voidaan löytää samoja ongelmia, mutta kaikilla menetelmillä löydettiin testeissä sellaisia ongelmia, joita ei muiden menetelmien suorituksen aikana kohdattu. ACM Computing Classification System (CCS): Human-centered computing → HCI design and evaluation methods
  • Peuraniemi, Tuukka (2015)
    Työssä tarkastellaan sähköisen lääkemääräyksen toteutusta, joka pohjautuu kliinisen dokumentin arkkitehtuuri -standardiin (Clinical Document Architecture, CDA). CDA puolestaan pohjautuu HL7 V3-sanomastandardiin (Health Level 7 Version 3). Aluksi työssä käydään läpi CDA-standardin rakenne ja tietotyypit sekä millaisia vaatimuksia se asettaa kliinisille dokumenteille. Tämän jälkeen tarkastellaan sähköisen lääkemääräyksen tietosisältöä ja rakennetta sekä CDA:n asettamien vaatimusten täyttymistä. Työn tavoitteena on hahmottaa sähköisen lääkemääräyksen rakenteen ongelmakohtia, määrittää sähköisen lääkemääräyksen elinkaari sekä tarkastella, mitä eResepti- ja sähköinen lääkemääräys -termeillä tarkoitetaan lääkemääräyksen elinkaaren kontekstissa. Lääkemääräyksen rakennetta tarkastellaan suhteessa CDA-standardin mukaiseen rakenteeseen. Elinkaaren rakennetta ja lääkemääräyksen prosessien vaikutusta siihen tarkastellaan sen aikana muodostuvan tietorakenteen avulla. Sähköisen lääkemääräyksen rakenteessa havaittiin jo CDA:sta juontuvia ongelmia tapahtuma-luokkien epäselkeässä käytössä dokumentin rakenneluokkina, epäeheissä tietokokonaisuuksissa sekä ei-tapahtumien kuvaamisessa tapahtuma-luokilla. Tapahtuma-luokkien ongelmat juontuvat HL7 V3:sta, joka myöskin kärsii tapahtuma-luokkien ristiriitaisesta tulkitsemisesta. Elinkaaren tietorakenteessa epäkohtia olivat viittausketjun katkeaminen sekä siihen liittyvät varmentamattomat solmut. Synonymisina käytettyjen termien eResepti ja sähköinen lääkemääräys havaittiin eroavan toisistaan. Sähköinen lääkemääräys tarkoittaa lääkemääräysdokumenttia korjauksineen, kun taas eResepti kattaa lääkemääräyksen lisäksi myös sen prosesseista syntyvät dokumentit.
  • Walkila, Sonya (2015)
    The grounds for debate on fundamental rights in the European Union are currently more fruitful than ever. Following the entry into force of the Lisbon Treaty, not only did the Union avail itself with its own Bill of Rights , i.e., the Charter of Fundamental Rights of the European Union, but is also preparing for its accession to the European Convention on Human Rights. By the same token, the Charter was elevated to the same level as other primary EU law. The frequent horizontal effect of fundamental rights in recent case law of the Court of Justice of the European Union is an indication of a stronger presence and the increased significance of fundamental rights in the Union s legal order at the time when the boundaries between the public and private spheres are increasingly blurred. The Court of Justice strives to interpret and apply the law in a way which contributes to a build-up of a coherent case law and conforms to fundamental rights as closely as possible. The immediate source of the jeopardising act or degree of the incurred effects should not prove decisive. Rather, the horizontal effect of fundamental rights contributes to the primacy, unity and effectiveness of European Union law . This study suggests it is feasible to consider the horizontal effect of fundamental rights as they relate to situations where the legal positions of private parties are transformed in the Hohfeldian sense pursuant to the application of those rights by a court in a legal dispute before it. The incurring legal position depends in turn on the degree of enforceability of the fundamental right norm in question. Because of the semantic and structural openness of fundamental right norms they often necessitate the deduction of a more concrete normative content. This concretization of abstract norms makes adjudicating on the basis of fundamental rights a delicate matter, since it gives great power to the courts. Where this power is extended to the area which typically falls in the sphere of private law, it grows even stronger. Besides powerfully serving to enhance the inner coherence and consistency of Union law and offering feasible solutions to legal problems, the horizontal application of fundamental rights implies a move towards a strengthened constitutional phase of the integration process. Arguments on fundamental rights entail much more than just formal or dogmatic disputes over the scope of application of an act of EU law. They touch on fundamental questions relating to the functioning of the Union and its constitutional nature which pertains to the entire legal order of the EU.